type OtherType = "sing" | "dance" | "rap" | string | number | null | undefined;

// NonNullable<T> 用来过滤null和undefined类型
// 确实keys一定是可以作为key的联合类型
type NonNullableType<T> = T extends null | undefined ? never : T;

type ResType = NonNullableType<OtherType>;

const res: ResType = "sing";

export {};
